Entangled Photon Emitter That Fits in Computer Chip Developed

Researchers at the Università degli Studi di Pavia in Italy has developed a component that can generate a steady stream of entangled photons. This device, called a micro-ring resonator, is tiny enough to fit in a standard silicon computer chip.

Entanglement may be the foundation of a new way to connect and transmit information. Entanglement is the mysterious connection between two particles where they interact with each other physically even when separated; regardless of distance. Einstein was quoted as describing this property as 'spooky action at a distance'.

In theory, even if the two photons are galaxies apart, they still interact with each other.

Current entangled photon emitters are too big to fit in a computer chip. The development of this micro-ring resonator is a step forward to secure communications and faster computers.

The resonators are loops etched onto the silicon chip. They can corral and re-emit particles of light as illustrated in the image above of the silicon ring resonator with its access waveguide. In the image, the green wave at the input represents the laser pump, the red and blue wave-packets at the output represent the generated photon pairs, and the infinity symbol linking the two outputs indicates the entanglement between the pair of photons.

Record 39 Minute Superposition State of Qubit - A Major Breakthrough in Quantum Computer Development

A normally fragile quantum state has been shown to survive at room temperature for a world record 39 minutes by Oxford University researchers. An artistic rendition of a 'bound exciton' quantum state used to prepare and read out information stored in the form of quantum bits.
Credit: © 2013 Stef Simmons with CC BY

Scientists have managed to keep a qubit in a superposition state for 39 minutes. The previous record for maintaining an atom in this state is 2 seconds.

This experiment is a big step forward for quantum computer technology.

Quantum computers are different that current computers (classical computers) in that information is stored in quantum bits (qubits) rather than in binary bits. Classical computers use bits that stores information in either an on or off state. A qubit ,aside from having an on and off state, can be in a superposition state where it can be both 1 and 0 at the same time. Photons, electrons, and atoms have been used in various experiments to serve as qubits.

In this case, the nuclei of a phosphorous atom in silicon was used as a qubit.

This superposition property of qubits is what makes a quantum computer powerful. Calculations and procedures can be done in fewer steps by a quantum computer compared to a classical computer. A calculation that may take 1 million steps for a classical computer to do, can be done in one step for a quantum computer.

Maintaining qubits in a superposition state has been a major obstacle in quantum computer technology. By being able to hold a qubit in this state for 39 minutes is a major breakthrough in the development of practical quantum computers. Long term information storage by qubits can be made possible because of this.

Overcoming Heisenberg's Uncertainty Principle In Polarization of Light Through The Direct Measurement Technique

Weak measurement: as light goes through a birefringent crystal the horizontally and vertically polarized components of light spread out in space, but an overlap between the two components remains when they emerge. In a “strong” measurement the two components would be fully separated.
Credit: Credit: Jonathan Leach

Researchers have developed a new technique that overcomes Heisenberg's Uncertainty Principle in measuring the polarization states of light.

The Uncertainty Principle was developed by a German theoretical physicist, Werner Karl Heisenberg. Known also as Heisenberg's Principle, the Uncertainty Principle states that the position and velocity cannot both be accurately known or measured at the same time. One may know the exact position but not the velocity and vice-versa.

This principle is one of the most famous underlying principle of quantum mechanics. In classical physics, it is easy to determine the exact momentum and position of a passing car at a specific time. But in quantum mechanics, where objects studied are at atomic and sub-atomic sizes, measuring both of these variables accurately at the same time becomes a problem.

This can be observed through the embedded video which shows MIT Professor Walter Lewin demonstrating the uncertainty principle with laser light. In it, he shows that as the position of the photons in the laser becomes more and more accurate, the direction of the laser light becomes wider and wider making it impossible to gauge its direction.

Recently, researchers believe they have a developed a technique that works around this bizarre behavior. This could lead to using light to encode information that can be read by quantum computers.

Quantum Algorithm Performing True Calculation Developed

A team of researchers have demonstrated a working quantum algorithm that performs a true calculation for the first time.

An algorithm is any well defined computational procedures that takes some value or set of values as input and produces some value or set of values as output. A mathematical functions are a kind of algorithm where it performs a procedure to come out with a value based on a problem with a defined set of input value or values.

There are also non-computational algorithms, such as directions to calling a person on the phone. The steps are sequential from picking up the phone, getting the number, dialing the number, etc. etc.

But procedures should cover all possibilities and the subsequent action it must take. Going back to the phone call example, the algorithm should include steps for situations where the phone gets a busy signal or that the phone number cannot be found.

In short, algorithms must take all situations that could arise into consideration.

Classical Computers and Quantum Computers

There are three ways to make a computer work faster. One is to make more computers (using multiple computers for one activity). Another is to make new computers faster. And the third is to make algorithms that lets computer do things faster.

Without an algorithm behind a program or application, computers won't be able to perform as it should.

Applying Magnetism and Microwave To Bismuth Atoms As Qubits For Quantum Computers

Researchers are looking at Bismuth atoms and nuclei as a source for qubits used in a quantum computer. Using magnetism and microwaves, they find that this process may be the next step to practical quantum computers.

Moore's law states that the processing power of a computer will continue to double every eighteen months. For the last 50 years, the law seems to be the norm. But technology is fast approaching the limit to the number of transistors that can fit into a silicon chip.

The current record for most number of transistors put on a chip is 2 billion.

By the year 2030, Moore's law would have brought computers to the atomic level. This would be the time of quantum computers. The speed and computing power of a quantum computer far surpasses that of present day computers (also called classical computers).

Hybrid Quantum Dot-Superconducting Resonator Device Developed For Quantum Computers

A classical computer holds information in bits. It is comparable to a series of switches that can be either off (0) or on (1). In a quantum computer, the fundamental unit is the qubit. A photon or electron is usually used for this. It is similar to a bit, using its spin, it can be in a 'down' spin (0) or an 'up' spin (1), or it can be both at the same time, a superposition state.

This property is unique in quantum mechanics. Because of superposition, a quantum computer can process a problem much faster than a classical computer can. Instead of solving a problem or initiating a process one step at a time like a classical computer, a quantum computer can do it all in one step.

Qubit On A Silicon Based Transistor For Quantum Computing Developed

The next evolution in computers is the quantum computer. With quantum computers, processors within utilize properties of atoms as dictated by quantum mechanics.

Classical computers (computers used today) use bits. Bits can be assigned either a 0 state or a 1 state to create a binary code. Using the 0 or 1 state, calculations are performed, information can be processed, and instructions followed.

Quantum computers use a different kind of bit; the qubit. Atoms generate spin, an up-spin and a down-spin, just like a regular computer bit, the up-spin and down-spin is similar to the 0 or 1 state. What makes the qubit special is that it also has a state called Superposition where the qubit is both up and down at the same time.

It is this superposition that makes quantum computing possible. An example would be an instruction to dial one million numbers. The classical computer would go about this by dialing the numbers one at a time. A quantum computer would dial all numbers in one step.

Technology is still far from constructing a practical quantum computer but each day, new developments are bringing it closer and closer to fruition. Early stage quantum computers the size of a room have already been built.

An often used principle when it comes to quantum computing is Moore's law. Moore's Law states that computer processing power continues to double every 18 months. This means that by the year 2030 or earlier, we will find that the circuits on a microprocessor will approach the atomic scale and quantum computing will be the norm.

Single-atom writer a landmark for quantum computing

A research team led by Australian engineers has created the first working quantum bit based on a single atom in silicon, opening the way to ultra-powerful quantum computers of the future.

In a landmark paper published today in the journal Nature, the team describes how it was able to both read and write information using the spin, or magnetic orientation, of an electron bound to a single phosphorus atom embedded in a silicon chip.

"For the first time, we have demonstrated the ability to represent and manipulate data on the spin to form a quantum bit, or 'qubit', the basic unit of data for a quantum computer," says Scientia Professor Andrew Dzurak. "This really is the key advance towards realising a silicon quantum computer based on single atoms."